[HPforGrownups] The Green Goo Again, and a new(!) view of the Tower (long)

[Kemper]

No: HPFGUIDX 165798

> ::Pippin does forehead slap::
>
> Bet you a butterbeer I know why Dumbledore seemed to know so much about
> that nasty green potion in the cave -- he knew the guy who
> invented it. Not Voldemort, of course, but the erstwhile ESE!Snape.
>
> That explains *everything*. Snape could have told Dumbledore all about
> it when he defected. Dumbledore could then recognize it from Snape's
> description, do that little spell only to confirm that this was indeed the
> nasty stuff Severus had told him about, and know immediately
> what he could and couldn't do.

Kemper now:
To add to your theory... Voldemort would want test the potion.
Perhaps while testing the potion, he could also test the loyalty of
his newest Potion Master DE.  Perhaps the potion drinker was one or
both of his parents: Dad, a Muggle; Mom, a Muggle-Lover.

This may be a reason for Snape leaving the Shadow for the Light.
(Personally, I like it better than Pining4Lily!Snape)

This would increase the tragedy and irony of Snape even further.

And perhaps Regulus learned of Snape's loyalty test which got him
thinking what his test would be for the Dark Lord.  Snape tells
Regulus about his potion, tells Regulus about its antidote.

Perhaps.

Kemper, presupposing possibilities and appreciating Pippin's post on the potion